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Abstract In the present study, ZnS and ZnO quantum dots (QDs) were synthesized via an all-aqueous process with polyethylene glycol (PEG) chains on their surface, and their toxicity as well as biodistribution were evaluated. No hemolysis occurred at a high concentration of 1600 μg/mL in vitro hemolytic assay, which demonstrated that the QDs-PEG displayed good blood compatibility. Following intravenous administration at 2, 6, and 20 mg/kg of the QDs-PEG in mice, the biodistribution, excretion, and biocompatibility were characterized at 1 h, 24 h, and 7 d. Quantitative analysis results indicated that the biodistribution trend of ZnS QDs-PEG was similar to that of ZnO QDs-PEG. The QDs-PEG were mainly trapped in the lung and liver, and almost removed from blood within 1 h. QDs-PEG were primarily excreted in feces at the 2 and 6 mg/kg doses. Coefficients, hematology, blood biochemistry, and histopathology results indicated that the QDs-PEG were safe and biocompatible.

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Selective enrichment or removal of specific proteins prior to analysis can minimize nonspecific interferences as well as information loss, which has been an important issue in current proteomics fields. In this work, two kinds of mesoporous silica SBA-15 (mean pore diameter of 5 nm and 7 nm), bifunctionalized with quaternary ammonium and C18 groups via silylanization reaction, was used to investigate the adsorption behavior for different proteins (bovine serum albumin (BSA), ovalbumin (OVA), hemoglobin (Hb), lysozyme (Lys) and cytochrome c (cyt c)). As possessing anion exchange (quaternary ammonium) groups, the bifunctionalized SBA-15 showed selective adsorption of the negative charged proteins, BSA and OVA. Based on these properties, sequential fractionation based on different SBA-15 materials as micropipette tip sorbents was developed for sample preparation prior to protein analysis. As expected, after the sequential treatment of the sample, the detection signal of the high abundant BSA was significantly decreased and that of the low abundant cyt c was obviously enlarged, which solved the problem that low abundant protein was suppressed by adjacent high abundant protein. The sample preparation technique significantly improved protein identification and this sequential fractionation approach could be potentially applied to extend information on the protein identification for biological samples with a wide dynamic range.

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Sulfonic acid-functionalized SBA-15 mesoporous molecular sieve (SBA-15-SO3H and SBA-15-po-SO3H) were synthesized by two post-synthesis methods. The functionalized SBA-15 materials were characterized and used to investigate the adsorption behavior for proteins (bovine serum albumin and cytochrome c) and polypeptides (insulin and glucagon) in the static and dynamic processes. The adsorption conditions: including adsorption time, pH and ionic strength of sample solution were investigated in the static adsorption mode. Under optimal conditions, SBA-15-SO3H and SBA-15-po-SO3H had a maximum capacity for insulin of 430 and 451 mg/g and for glucagon of 1303 and 1094 mg/g, respectively. In addition, the two functionalized SBA-15 mesoporous materials showed selectively adsorption of proteins in the dynamic adsorption mode. Compared with SBA-15, the surface modification of SBA-15 was responsible for the selective adsorption of proteins and high adsorption capacity for some biomolecules. It indicated that the two functionalized materials could be used as adsorbents to immobilize or separate biomolecules.Graphical abstractResearch highlights► Two strong cation-exchange SO3H modified SBA-15 materials were synthesized. ► Two modified SBA-15 could selectively adsorb proteins in the dynamic mode. ► Two modified SBA-15 had large loading capacity for polypeptides in the static mode.

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The mechanism of interaction between mangiferin (MA) and bovine serum albumin (BSA) in aqueous solution was investigated by fluorescence spectra, synchronous fluorescence spectra, absorbance spectra and Fourier transform infrared (FT-IR) spectroscopy. The binding constants and binding sites of MA to BSA at different reaction times were calculated. And the distance between MA and BSA was estimated to be 5.20 nm based on Föster's theory. In addition, synchronous fluorescence and FT-IR measurements revealed that the secondary structures of the protein changed after the interaction of MA with BSA. As a conclusion, the interaction between the anti-diabetes Chinese medicine MA and BSA may provide some significant information for the mechanism of the traditional chinese medicine MA on the protein level to cure diabetes or other diseases.